Clinical research on the drug resistance bacteria and related genetic testing in the tissue samples of cavitary pulmonary tuberculosis.

Objectives:To compare the cultured positive rates of Mycobacterium tuberculosis and their detective consistency between the tissue samples of cavitary pulmonary tuberculosis and sputum samples,and to probe clinical significance of the detection of multidrug-resistant Mycobacterium tuberculosis by directly using the tissue samples of pulmonary tuberculosis based on rpoB gene and the KatG gene mutation detection in the important role of diagnosing multidrug-resistant Mycobacterium tuberculosis.Methods:Mycobacterium in the preoperative and postoperative sputum samples and the tissue samples resected by surgery from the patients with pulmonary tuberculosis were cultured by the rapid bacterial culture system of BacT ALERT 3D,cultured positive strains of which were identified in strains.The drug sensitivities of isoniazid(H) and rifampicin(R) in the isolated strains of Mycobacterium tuberculosis were respectively tested by the absolute concentration method,in which the consistency between the sputum samples and the tissue samples were compared.The gene fragments of Mycobacterium rpoB and KatG in the resected tissue samples were amplified by the specific primers,the results of which were compared with those of the culture.Results:In 62 cases,there were 22 cases of preoperative sputum culture positive,in which the positive rate was 35.5%(22/62).The drug sensitive test showed 18 cases of drug resistance,16 only resistance to isoniazid,13 only resistance to rifampin,12 resistance to both isoniazid and rifampin.There were 34 cases of culture-positive of Mycobacterium tuberculosis in 62 cases of tuberculose focus,showing the positive rate of 55%(34/62),30 cases of drug resistance,26 only resistance to isoniazid,20 only resistance to rifampin,17 resistance to both isoniazid and rifampin.22 cases of katG gene mutations related INH resistance,18 cases of rpoB gene mutations related RFP resistance and 16 cases of the mutation of both genes were found by the drug resistance gene testing in 62 cases of the tuberculosis tissues.There were not the mutation of both genes in all the tissues for the sensitive strains of Mycobacterium tuberculosis verified by the drug sensitivity test.16 0f 18 cases of rpoB gene mutations were found simultaneously katG gene mutations(89%,16/18).Conclusions:There is a good consistency between the results of etiology testing in the resected lung tissue samples from thick walled cavity of the patients with pulmonary tuberculosis and those of their sputum samples and the positive rate of Mycobacterium tuberculosis culture in the resected lung tissue samples is higher than that of sputum culture.It can also be carried out that Mycobacterium tuberculosis rpoB gene and KatG gene testing by using the tissue samples can guide promptly and exactly clinical pharmacotherapy of postoperative anti-TB drugs.